马铃薯热激转录因子HsfA3基因的克隆及其耐热性功能分析     

唐锐敏  贾小云  朱文娇  印敬明  杨清 《作物学报》2021,(4):672-683

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Variability in the performance of juvenile Chinook salmon is explained primarily by when and where they resided in estuarine habitats          下载免费PDF全文

Paul Chittaro  Lyndal Johnson  David Teel  Paul Moran  Sean Sol  Kate Macneale  Richard Zabel 《Ecology of Freshwater Fish》2018,27(3):857-873

Estuarine habitats provide rearing opportunities for the juvenile life stage of anadromous fishes. Because survival is positively correlated with juvenile performance, these estuarine habitats play an important role in population abundance and productivity. To provide information for the recovery of several depressed stocks of Chinook salmon in the Columbia River Basin, we sought to identify the factors that explain variability in performance. Using otolith‐derived estimates of juvenile somatic growth rate as an index of recent performance, we observed a negative nonlinear relationship between growth rate and day of year, and a decreasing and increasing trend of growth rate over the 8 years of this study and distance from the river mouth respectively. Using a generalised linear modelling approach, we found that variability in juvenile somatic growth rate was best explained by where and when individuals were collected, their body size, contaminant loads, stock of origin, and whether a fish was hatchery produced or unmarked. Lastly, we argue that a considerable improvement to the growth rate of juveniles in estuarine habitats is physiologically possible. The results of this 8‐year study provide a baseline of the performance of juvenile Chinook salmon to evaluate habitat restoration programs and to compare against future anthropogenic conditions.  相似文献   

Identification of an H1N1 subtype of swine influenza virus and serological analysis     

Fa-chao SUN  Min TAN  Yuan-chao ZHANG  Yu-chao WANG  Sheng-liang CAO  Guo-fei DING  Fang-yuan CONG  Li-hong GUO  Si-dang LIU  Yi-hong XIAO 《农业科学学报》2019,18(7):1436-1442

To investigate the epizootic of swine influenza virus(SIV), 60 nasal swabs were collected from a clinical cases of pig farm in Tai'an City, Shandong Province of China in April 2017. SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced. An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1). Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch, seven genome segments belonged to avian-like H1N1 influenza virus lineage. The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G, which is a typical molecular biological characteristic. Five potential N-glycosylation sites(N14, N26, N277, N484 and N543) were found in the HA gene. To further investigate the epidemiology of SIV in this farm, the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens. The results showed that the total positive rate was 65.43%. The positive rates of single virus infection detected by EAH1N1, 2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35, 30.85 and 7.47%, respectively. The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm. These data provide evidence of an epizootic of SIV.  相似文献   

猪繁殖性状的遗传改良策略     

李玉华  曾勇庆 《猪业科学》2003,20(1):11-14

猪繁殖性能的提高将为养猪业带来巨大的经济效益 ,目前多数育种者将提高猪的繁殖力作为主要育种目标 ,并用数学遗传学方法和分子育种技术对繁殖性状进行改良。  相似文献   

基于模糊建模的混炼胶粘度测量     

樊绍胜  王耀南 《湖南农业大学学报(自然科学版)》2004,31(3)

提出了一种在线测量混炼胶粘度的新方法．该方法以模糊建模技术为基础，综合考虑混炼过程各因素对胶料粘度的影响，建立起胶料粘度的在线测量模型．在模糊建模中，采用T-S模型描述胶料粘度变化的非线性过程，提出了一种基于相似性判别的模糊聚类算法以自动确定合适的聚类组数目，并用实数编码的遗传算法优化全局参数，从而获得了规则简化的、具有较高精度的模糊模型．根据此方法，设计了测量装置，并进行了现场试验．试验结果表明模糊模型输出与实验室测量值基本一致，平均误差较低且最大误差未超过1门尼．该方法较大地提高了橡胶混炼的生产效率，为粘度最优控制奠定了基础．  相似文献   

山东境内五个山羊种群生化遗传多态性研究     

韩海霞  王建民  王桂芝  孙允东  张宁波  苑存忠 《家畜生态》2006,(6)

应用聚丙烯酰胺凝胶电泳法(PAGE),对山东省境内山羊种群的血液生化遗传标记多态性进行分析。结果表明,所测5个山羊品种中,Tf、Akp及EsⅠ基因座均表现出多态性,Hb和EsⅡ基因座仅分别在崂山奶山羊和莱芜黑山羊品种中表现出多态性,Amy未表现出多态性;平均杂合度为0.2876,基因纯合系数在0.6以上,群体的遗传分化系数为0.02614,说明这些山羊群体的遗传变异较低,其97.386%来自群体内遗传多态现象。基于3个多态位点基因频率的系统发育分析证明,带有共同遗传基础的济宁青山羊、鲁北白山羊和崂山奶山羊遗传距离较近,引进的南非波尔山羊与4个地方山羊品种遗传距离最远。  相似文献   

沙黄松选择增益结构模式初步研究     

周东雄  李兆丰 《福建林业科技》1994,21(2):10-14

采用沙黄松天然林自由授粉家系７年生树干材积的材料，分析了联合选择遗传增益结构模式。结果表明：亚群体间存在极显著差异，亚群体内家系间差异不显著；联合选择增益结构模式为亚群体间７２．４４％、亚群体内家系间３．５５％、单株间２４．０１％。  相似文献   

金属热防护系统多层隔热材料的传热分析及参数优化     

闫长海  曲寿江  孟松鹤  陈贵清  杜善义  刘国仟 《勤云标准版测试》2006,(4):257-263

采用能量平衡方程和离散坐标法近似地建立了金属热防护系统多层隔热材料的一维稳态传热的数学模型，并利用遗传算法和纤维隔热材料的有效导热系数试验数据求解传热反问题，从而得到了模型中的纤维隔热材料的辐射衰减系数、反照率和隔热屏表面辐射发射系数。最后，由实验测得了多层隔热材料的有效导热系数，验证了采用优化参数后，多层隔热材料的传热模型的正确性。  相似文献   

Genetic diversity of herbicide-resistant and -susceptible Avena fatua populations in North Dakota and Minnesota     

L W MENGISTU  C G MESSERSMITH  & M J CHRISTOFFERS 《Weed Research》2005,45(6):413-423

Genetic diversity within and among 20 herbicide-resistant (HR) and 16 herbicide-susceptible (HS) Avena fatua multi-field populations was determined using 82 polymorphic loci resulting from two intersimple sequence repeat (ISSR) primers and one long-primer random amplified polymorphic DNA (LP-RAPD) primer. Collections from the Red River Valley of North Dakota and Minnesota, sampled in 1964 and 2000, represented A. fatua populations before and after intensive exposure to herbicides. A 1995 collection from south-west North Dakota represented A. fatua exposed to low herbicide selection. Despite differences in years of herbicide exposure among collections, both HR and HS populations from every collection maintained nearly similar levels of ISSR and RAPD diversity. Genetic differentiation among populations (G_ST) varied from 11% to 13% among HR populations and from 9% to 16% among HS populations, indicating that 84–91% of total variation remained within HS or within HR populations. Minimal difference in gene diversity between HR and HS is consistent with multiple origins of resistance, where HR A. fatua most likely evolved from diverse founding individuals.  相似文献   

湖羊生长性状遗传参数的估测     

徐宁迎  戴旭明  韩玉刚  田丽琴 《浙江大学学报(农业与生命科学版)》1994,(1)

对湖羊生长性状的表型参数和遗传参数的估测表明，性别对这些生长性状有极显著的影响，在遗传参数的估测中剔除性别的效应可提高估计的正确性。初生重、断奶重、三月龄重、六月龄重、周岁重和日增重等性状都属于高遗传力性状，遗传力分别为０．４１９０，０．３０４２．０．６０２３，０．６０７７，０．３９５６和０．６９４５．根据相关分析结果，为提高湖羊的生长速度和肉用性能，把日增重和三月龄重作为主要选择性状，预期可获得较好的效果  相似文献